The Tory leader also heaped praise on the Welsh rugby team but added that like captain Sam Warburton, who was sent off in the world cup semi-finals against France, he had "had a bit of a run-in with the French recently".

He told guests that Downing Street had become a "Welsh outpost" for the evening after a faulty flagpole meant the Union Jack was taken down in favour of the Red Dragon.

"I want you all to know that we are flying the Welsh flag over Number 10 Downing Street tonight.

"Normally the Welsh flag would fly alongside the Union Jack, but we can’t; we only have one working flagpole, so this is entirely a Welsh outpost as we speak tonight," he said.

But he dashed hopes of Welsh pleas for St David's Day to be turned into a bank holiday, blaming Chancellor George Osborne who does not like "anything that reduces GDP by even 0.01%".

The Prime Minister has previously admitted his love of the BBC sitcom about the long distance relationship between Essex boy Gavin, played by Mathew Horne, and Stacey, from Barry in the Vale of Glamorgan, Wales.

Mr Cameron confessed to using the show’s catchphrases such as “what’s occurring?” and “tidy”.

He said: “I've been to Barry three times and want to go back. From now on, whenever we have an election success in Wales, I'm going to congratulate my Welsh MPs on a 'tidy' result.”

Mr Cameron said the show, written by James Corden and Ruth Jones, appealed to him because he enjoys “a bit of happy escapism” to unwind after a tough day running the country.

Cheryl Gillan, the Welsh Secretary, yesterday revealed in the House of Commons that she had given Mr Cameron a bunch of daffodils from the National Botanic Garden of Wales to mark St David’s Day.

Campaigners in Wales have been pushing for several years for their nations’ patron saint’s day to be made a national holiday, however, MPs have voiced concerns over the economic cost of the move.

Members of the National Assembly for Wales voted unanimously in 2000 to back St David's Day as a national holiday.

Proposals last year from the Department for Culture, Media and Sport suggested the early May bank holiday could be moved to March 1 exclusively for Wales.